Noise check

[squaregoldfish]

We can add a check for the standard deviation of the whole data set. Atmospheric pressure can be noisier than ocean CO2, for example.

[squaregoldfish]

For the Benguela Stream, Ute has checks on the standard deviation in each measurement sequence (between standard runs). This would be a good enhancement to have, if we can reliably detect each 'run' (probably by gaps in the data).